The South American caecilian
Siphonops annulatus takes dedication to an unusual extreme by allowing her offspring to eat her skin. Alexander Kupfer of the Friedrich-Schiller University in Jena, Germany, and his colleagues report that
S. annulatus nestlings have 44 spoon-shaped teeth. These teeth bear claw-like protrusions that the nestlings use to tear away the outer layer of their mother's skin. The same group has previously described "maternal dermatophagy", as such skin-feasting is called, in an African amphibian,
Boulengerula taitanus. It therefore seems likely that the behaviour arose before Africa and South America separated, more than 100 million years ago.
One hundred million years
of skin feeding? Extended parental care in a Neotropical caecilian. Biol. Lett. doi:10.1098/rsbl.2008.0217Maternal dermatophagy, the eating of maternal skin by offspring, is an unusual form of parental investment involving co-evolved specializations of both maternal skin and offspring dentition, which has been recently discovered in an African caecilian amphibian. Here we report the discovery of this form of parental care in a second, distantly related Neotropical species
Siphonops annulatus, where it is characterized by the same syndrome of maternal and offspring specializations. The detailed similarities of skin feeding in different caecilian species provide strong evidence of its homology, implying its presence in the last common ancestor of these species. Biogeographic considerations, the separation of Africa and South American land masses and inferred timescales of amphibian diversification all suggest that skin feeding is an ancient form of parental care in caecilians, which has probably persisted in multiple lineages for more than 100Myr. These inferences support the hypotheses that (i) maternal dermatophagy is widespread in oviparous direct-developing caecilians, and (ii) that viviparous caecilians that feed on the hypertrophied maternal oviduct evolved from skin-feeding ancestors. In addition to skin-feeding, young
S. annulatus were observed to congregate around, and imbibe liquid exuded from, the maternal cloacal opening.
The recent decline of frogs worldwide is now well established but the causes of this decline remain unclear. Australia has a highly diverse and species-rich frog fauna and a number of species have declined significantly over the last 30 years. Two iconic species in particular have been the subject of considerable concern because their decline has been so rapid and extreme. The northern corroboree frog, Pseudophryne pengilleyi, and the southern corroboree frog, Pseudophryne corroboree, are small, pond-breeding and very brightly coloured terrestrial frogs restricted parts of the alpine and subalpine regions of the southern highlands of New South Wales and the Australian Capital Territory in Australia. The rapid decline of both species of corroboree frog is noteworthy because it has been so well documented. In response to the continued decline and critically low population size, a captive husbandry programme has commenced. This recovery action currently includes (i) collection of eggs from the wild each summer with captive rearing of tadpoles through to metamorphosis and subsequent re-introduction of frogs to the wild, and (ii) establishment of a captive breeding colony for producing frogs for re-introduction. An understanding of the magnitude and patterns of genetic diversity among populations is critical for conservation efforts attempting to maintain evolutionarily viable species.
Proteins encoded by genes of the major histocompatibility complex (MHC) play an essential role in the adaptive immune response of vertebrates. Populations in areas of postglacial expansion are not only of recent origin, but often occur at the margins of species’ ranges. Peripheral populations may be more prone to extinction because of small population sizes and suboptimal environmental conditions. Small populations may also exhibit lower adaptive potential because of environmental stress and genetic problems. Studies of MHC variation in marginal populations inhabiting previously glaciated areas are of great interest. The Alpine newt, Mesotriton alpestris, has an extensive and complex geographical distribution in Europe.
A mass die-off of imported red tailed knobby newts (Tylototriton kweichowensis) occurred in 2004 in Belgium and the Netherlands. In addition to massive infection with Rhabdias tokyoensis, Ranavirus was isolated from three dead newts examined virologically and the gene coding for the major capsid protein of the virus was sequenced. The isolate showed 99.8% similarity to the published sequence of frog virus 3. Upon experimental infection of axolotls (Ambystoma mexicanum) with this isolate, no marked pathology was noticed and the virus could not be re-isolated at 9 weeks post-inoculation. Apart from the possibility of exposure of a non-sensitive host, the mortality episode in the newts may be related to stress resulting from the importation of the newts in breeding condition. This possibility is supported by the presence of degenerating egg-follicles in the females.
